Axial cylinder pump especially intended for moving liquids



Dec. 12, 1950 l.. wlDMl-:R 2,534,153 AXIAL CYLINDER PUMP, ESPECIALLY INTENDED FOR MOVING LIQUIDS Filed May l, 1946 www Patented Dec. 12, 1950 UNITED STATE-S AXIAL CYLINDER PUMP ESPECIALLY INTENDED FOR MOVING LIQUIDS Leo Widmer, Feldbach-Zurich, Switzerland, assigner to Schweizerische Lokomotvund Maschinenfabrik, Winterthur, Switzerland Application May 1, 1946, SerialNo. 666,308 In Switzerland March 11, 1946 3 Claims.

lator parts mounted on the said shaft are enlgaged by the full torque of the pump shaft.

Also it is known in the art to so operate axial pistons with adjustable stroke, by means of a rotating cam disc, that the pistons contact the cam for a longer or shorter period of time by virtue of axially displacing the cam disc and thus correspondingly perform a greater or lesser stroke of the pistons.

PATENT GFFICE which the pistons 8 operate. The latter are brought to bear against the skew `disc ID by means of the springs 9 and contact vsame along generating lines of the conically tapered piston heads Il. Lateral apertures I3 are provided in the bores I and provide communication between the latter and the jacket space Ia. The latter is filled with liquid up to a level 22 approximately. The ends of the cylinder bores are closed off by spring-loaded balls I4 from the delivery chamber 28, which balls act as check valves.

The skew disc I0, by means of the ball bearings 16 and I1, is rotatably mounted, in an lnclined position relative to the drive shaft i8, on

the catch plate I9 non-rotatably secured to the The piston heads, whicyjfA abut against the cam disc for a certain lengthy!" of time only, thus are subjected to heavy impacts when being contacted by the cam, exceptwhen being set for full stroke. The piston heads and the cam thus are subjected to a very pronounced wear and tear and even may fail in operation.

In the design of an axial-piston engine according to the present invention, the adjustment of the inclination -of the skew disc and the irnpactwise operation of the pistons is avoided by combining the piston drive, operated by means of an axially adjustable skew disc which always is positively engaged by the pistons, with a control regulating the beginning of the Working stroke proper by having the pistons close off an opening in the cylinder walls. The said combination of piston drive and working-stroke control is of such character that an axial displacement of the skew disc relative to the cylinder-wall openings gives rise to a change of the piston course utilizable for pumping purposes.

One embodiment of the present inventionmis illustrated in the drawing, in which: Fig. 1 shows a longitudinal section of a pump with horizontal axis of rotation,

Fig. 2 a similar section of a modied disposi- -tion of the drive gear in a pump with vertical axis of rotation,

Fig. 3 a partial cross-section on the line III-III of Fig. 1, and

drive shaft I8. The latter is mounted in the inner casing 4 and the 'cylinder block 5 -on the 'ball bearings 2B and 2|.

The catch plate or driver I9 is bearing against the adjusting socket or thimble 25 through the intermediary Iof the thrust ball bearing 23. The said socket 25 is a sliding fit in the inner casting II and is rotated therein when axially displaced on the threads 24. The adjusting socket 25 is axially Adisplaced by the worm wheel 21 journaled in the inner casing 4 and engaging the worm rim 26.

When the drive shaft I8 is rotating, the `pistons 8 reciprocate axially, During each working cycle v(to-and-fro motion) of the pistons, the apertures I3 are uninasked once lso that the liquid to be pumped may pass therethrough from the jacket space I a into the -cylinder bores l'I. After an aperture I3 is again masked 'by a piston 8, Athe liquid trapped in the respective bore 'l'A is shot through the check valve vI4 into the delivery chamber 28 and out therefrom through the riser 29. The apertures must be so dimensioned that the time during which they are unmasked by the pistons is sulcient to permit of iilling the cylinder bore 'I with liquid from the jacket space I a, which latter e. g. may be under atmospheric pressure.

When the adjusting socket or thirnble 25 occupies the axial position according 'to Fig. 1, that portion of the piston stroke which serves for raising liquid is identical with the dist/ance S.

Fig. 4 a partial longitudinal section of a modii. e. with the overlap of the butt face lI2 of the piston 8 relative to the edge I5 of the aperture I3. When the thimble 25 then is withdrawn or isplaced to the left, the said overlap and thus the useful piston stroke S and the pump output is less. When the thimble 25 is displaced so far to the left that the piston butt-face I2 at the end of the piston stroke only extends up to the edge I5, the `pump output 'is zero (no-load), and

' the liquid, in spite of the pistons 8 operating with full stroke, is sucked through the `ports I3 into the cylinder bores 'I only to be discharged therethrough again, i. e. no pressure is being travel.

Yiiow into the cylinder bores l.

built up in the bores 1 and the valves I4 remain closed. v I

The design according to Fig. 2, only showing the adjusting-socket portion of the pump, but in vertical disposition, diifers from that of Fig. 1 in that the socket 39 axially guided in the inner casing 4 is not adjustable by means of threads, but is displaced by a spring 3| abutting with its top end against the stationary casingcover 32. The degree of compression of the spring 3l is defined by the total pressure of the pistons S subjected to the pressure of the delivered liquid. When the pressure to be overcome by the pistons 8 is high, the spring 3l is more compressed and the output thus automatically decreased owing to the lesser useful piston The reverse holds true when the pressure to be overcome by the pistons becomes smaller. In this manner, the pump output advantageously may be decreased at a higher pump pressure without loss of power, and increased at a lesser discharge head.

The suction ilow into the bores 'l may be improved or accelerated by insertingas shown in Fig. 4-suction stand-pipes 35 into the cylinder walls, wherein balls 36 serving as check valves are disposed. During a pressure stroke, the said balls are pressed against the restricted apertures 31 of the stand-pipes 35. During a suction stroke, the balls 36 are brought to abut against the perforated steps 3S so that the liquid may The overflow function of the port I3 remains intact in such a disposition. Such auxiliary suction line is provided for in cases, e.- g., when it is desired that the: pistons be sucking liquid from the jacket space iq from the very beginning of the suction stroke, in contrast to the design of Fig. 1 wherein suction is starting only at the moment when the port i3 is unmasked by the piston 8.

What I claim and desire to secure by Letters Patent is:

1. A pump, especially intended for moving liquids, comprising a drive shaft, a cylinder block,

a plurality of cylinders in said block arranged in parallel and in a circle concentric with said drive shaft, a piston reciprocable in each cylinder, each cylinder having an inlet port over which the end of the piston slides, an oblique disk of constant slant associated with said pistons in power transmitting relation, a carrier member for said disk mounted for rotation with said drive shaft and for axial movement along said shaft to vary the beginning of the pressure stroke of the pistons by axial movement of said oblique i. disk relatively to said inlet openings, said disk` being rotatably journalled on the carrier member, a stationary casing secured to said cylinder block vand surrounding said carrier member and oblique disk, an axially movable sleeve member disposed concentrically with said drive shaft and having a larger diameter than said oblique disk, said sleeve member being guided for axial movement within said casing, and a thrust bearing mounted between said sleeve member and said carrier member for directly transmitting axial thrust from one member to the other.

2. A pump, especially intended for moving ,i liquids, comprising a drive shaft, a cylinder block, `a plurality of cylinders in said block arranged in parallel and in a circle concentric withv .said drive shaft, a piston reciprocable in each cylinder, each cylinder having an inlet port over j which the end of the piston slides, an oblique disk of constant slant associated with said pistons in power transmitting relation, a carrier member for said disk mounted for rotation with said drive shaft and for axial movement along said shaft to vary the beginning of the pressure stroke of the pistons by axial movement of said oblique disk relatively to said inlet openings, said disk bein g rotatably journalled on the carrier member, a stationary casing secured to said cylinder block and surrounding said carrier member and oblique disk, an axially movable sleeve member disposed concentrically with said drive shaft and having a larger diameter than said oblique disk, said sleeve member being guided for axial movement within said casing, a threaded hollow stud on said sleeve member and engaging a complementary thread provided on said casing, a worm drive operatively connected to said sleeve member to rotate the latter and thereby cause axial adjustmentthereof, and a thrust bearing disposed between said sleeve member and said carrier member for directly transmitting axial movement from the sleeve member to the carrier member.

3. A pump, especially intended for moving liquids, comprising a drive shaft, a cylinder block, a plurality of cylinders in said block arranged in parallel and in a circle concentric with said drive shaft, a piston reciprocable in each cylinder, each cylinder having an inlet port over which the end of the piston slides, an oblique disk of constant slant associated with said pistons in power transmitting relation, a carrier member for said disk .mounted for rotation with said drive shaft and for axial movement along said shaft to vary the beginning oi the pressure stroke of the pistons by axial movement of said oblique disk relatively to said inlet openings, said f' disk being rotatably journalled on the carrier member, a stationary casing secured to said cylinder block and surrounding said carrier member and oblique disk, an axially movable sleeve member disposed concentrically with said drive shaft and having a larger diameter than said oblique disk, said sleeve member being guided for axial movement within said casing, resilient means between said axially movable sleeve member and said stationary casing to elastically support the sleeve so that a smaller effective stroke of the pistons will produce a larger delivery pressure and a larger eiective stroke a smaller delivery pressure.

LEO WIDMER..

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,933,081 Stephan Oct. 31, 1933 1,952,994 Laird Mar. 27, 1934 1,970,679 Walker et al Aug. 2l, 1934 2,165,696 Charter July 11, 1939 2,169,456 Wahlmark Aug. 15, 1939 2,193,612 Alden Mar. 12, 1940 FOREIGN PATENTS Number Country Date 316,885 Germany Dec. 6, 1919 388,599 Great Britain 1933 396,973 Germany 1923 601,911 France Dec. 11, 1925 Certificate of Correction Patent No. 2,534,153 December 12, 1950 LEO WIDMER It is hereby certified that error appears in the above numbered patent requiring correction as follows:

In the heading to the printed specification, line 8, foreign filing date, for March 11, 1946 read March 8, 1.956;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of June, A. D. 1951.

[SML] THOMAS F. MURPHY,

Assistant @ammissioner of Patents. 

